Low molecular weight hydrocarbon polymers are widely used in a variety of applications, such as, in printing inks, processing aids, mould release agents, candles, polishes, and particularly, in coatings and adhesives. In particular, highly crystalline polymers are attracting increasing interest for admixing with other components to produce abrasion-resistant printing inks. These polymers are also used for paint flatting, and for the preparation of emulsifiable waxes for cleaning materials. An important application is in hot melt systems, particularly, hot melt coatings and hot melt adhesives. In general, paraffin waxes or microcrystalline waxes are used in such hot melt applications, but paraffin waxes and soft microcrystalline waxes both have relatively low melting points. Hard microcrystalline waxes have higher melting points, but are relatively expensive and have high viscosity. In some systems they also give rise to incompatibility problems.
International Publication No. WO 03/087178 discloses an article of manufacture, which comprises a copolymer of ethylene and vinyl aromatic monomer having a molecular weight less than 15,000. Preferably, the copolymer is characterized by a backbone having a first and second terminal end groups. The first terminal end group is a methyl group, and the second terminal end group is a vinyl group, and the ratio of the terminal methyl group to the terminal vinyl group is 0.8:1 to 1:0.8.
U.S. Pat. No. 5,433,757 discloses an oil-soluble fuel and lubricating oil additive, comprising at least one terminally unsaturated ethylene/α-olefin polymer of 300 to 20,000 number average molecular weight, substituted with mono- or dicarboxylic acid producing moieties. The terminal unsaturation comprises terminal ethenylidene unsaturation.
International Publication No. WO 2004/031292 discloses a thermoplastic composition comprising the following: (i) from 1 to 99 percent, by weight, of the total composition, of at least one thermoplastic copolymer, for example, a styrene block copolymer, and (ii) from 1 to 99 percent, by weight, of the total composition, of at least one homogeneously branched ethylene/α-olefin interpolymer, for example, an ethylene/1-octene having a density less than, or equal to, 0.899 g/cc, and a Brookfield viscosity of greater than 500 cP (350° F.).
U.S. Pat. No. 6,100,224 discloses a copolymer comprising units of an unsaturated dicarboxylic monomer and an ethylene/α-olefin macromer. The macromer is an unsaturated ethylene/α-olefin polymer comprising units from ethylene and at least one α-olefin represented by the formula CH2═CHRa, where Ra is a C1-C18 linear alkyl group or a C3-C18 branched alkyl group. The ethylene/α-olefin polymer has a number average molecular weight from about 500 to 100,000, and at least 30% of the unsaturation in the ethylene/α-olefin polymer is terminal vinylidene.
The copolymer has a carbon-carbon backbone, and contains succinic groups and hydrocarbyl groups. The copolymer can be derivatized by reaction with nucleophilic reactants, including monoamines, polyamines, monoalcohols, polyols, amino alcohols, reactant metal compounds and mixtures thereof. The derivatized copolymers can be post-treated with one or more post-treating agents.
International Publication No. WO 2004/035680 discloses highly filled polymer compositions comprising a low molecular weight ethylene and/or alpha olefin homopolymers and copolymers, or blends thereof, and filled with high concentrations of fillers or additives.
International Publication No. WO 2005/100501 discloses an article comprising a functional component, a tackifier, and an olefin polymer. The olefin polymer comprises one or more C3 to C40 olefins, and optionally, one or more diolefins, and less than 5 mole of ethylene, and has a Dot T-Peel of 1N or more, an Mw of 100,000 or less, a branching index (g′) of 0.95 or less, measured at the Mz of the polymer. The functionalization component is selected from functionalized polymers, functionalized oligomers or beta nucleating agents.
U.S. Pat. No. 6,875,816 discloses a composition comprising a high molecular weight, branched component, and a low molecular weight, branched component. Some of the disclosed polymer compositions are characterized by a substantial absent of amyl or methyl branches, and a melt strength (MS) that satisfies the following relationship: MS≧x/l2+y.
International Publication No. WO 2002/36651 discloses propylene ethylene copolymers with an ethylene content between 8 and 32 mole percent, and grafted with maleic anhydride and a peroxide. Additional polyolefin-based compositions are disclosed in WO 2005/111145.
There remains a need for lower molecular weight ethylene polymers with the appropriate balance of viscosity and crystallinity for use in coatings, adhesives and other applications. Also, there is a need for functionalized lower molecular weight ethylene polymers with the appropriate balance of viscosity, vinyl content and crystallinity for improved adhesion and other applications. At least some of these needs and others have been met by the following invention.